Tool and tool retainer



Nov. 6, 1928.

J. 5. DONALDSON TOOL AND TOOL RETAINER Filed Nov. 24, 1925 2 Sheets-Sheet 1 I en's-Bra g 44; ATTORNEY INVENTOR- Nov. 6, 1928. 1,690,571

- J. 5. DONALDSON TOOL AND TOOL RETAINER Filed Nov. 24, 1925 2 Sheets-Sheet 2 A INVENTOR I ATTORNEY Patented Nov. 6, 1928.

UNITED STATES PATENT orr ce.

"JOHNSHEARMAN, DONALDSON, OF NEW YORK, N. Y.

TOOL AND Toot RETAINER.

Application med November 24, 1923. Serial No. 676 742.

This invention relates to tools and tool retainers for automatic cutting and hammering devices to which. the generic term pneumatic chisels may be applied. An object of the invention is to provide a pneu matic chiselwith a tool retainer which may be adjusted to vary the force of the hammer blows on the tool so as to adapt the device either for heavy rough cutting, riveting, or other pounding, or for fine carving, orfor any intermediate work.

United States Patent No. 1.4%,461, issued to me on January 30, 1923, describes a tool retainer for pneumatic chisels which holds a tool in operative relation with the hammer of the chisel and enables a workman to turn and guide the tool without grasping it with his hand. The present invention may be incorporated in a device of the type described in that patent, and when so used serves to give a workman using a pneumatic chisel as complete control over the operation of the tool as he has heretofore obtained by .grasping the tool in his hand, while at the same time the'workman is protected from the injury which results from grasping a vibrating hammer-driven tool.

The present invention aims generally to improve the construction and operation of the device shown in my aforesaid patent. A tool retainer embodying the present invention may, like that shown in the former patent, be providedwith two tool-engagmg members, one of which is so mounted that it cannot be rotated with respect to the tool retainer and is adapted to hold the tool in the retainer but to permit the withdrawal of the tool when the tool is turned in one direction, and the other of which fits upon the tool in such a way as to prevent turning of the tool with respect to it and is rotatably mounted in the retainer and provided with releasable locking means by which its rotation may be prevented. According to the present invention the non-rotary toolengaging member is held between two springs, and means are provided for adjusting its normal position to regulate the force of the hammer blows on the tool. Furthermore, the releasable locking means for the rotatably mounted tool-engaging member is normally held in looking posi handle;

tion by the thrust of one of these springs so that no additional spring is required for the locking means.

Other features and advantages of the in vention are hereinafter set forth in connection with a detailed description of the specific embodiment of the invention which is illustrated in the accompanying drawings, in which I Fig. lis aside view of a complete pneu matic chisel provided with my improved tool retainer, showing parts in section, and showing the locking sleeve pulled back to permit a release of the'tool from the retainer;

Fig. 2 is an enlarged longitudinal section taken on the line 22 of Fig. 1 showing the lockingsleeve in its operative position in whichit prevents removing the tool from the retainer; and

Figs. 3, t and 5 are transverse sections taken on the lines 33, 4-4 and 5-5 of Fig. 2, respectively. i

The drawings show the tool retainer applied to the ordinary barrel 10 of a pneumatic chisel. The barrel 10 contains the usual pneumatically operated hammer, the outer end 11 of which is shown in Fig. The outer end 12 of the barrel 10 is provided wit-h'the customary central opening to admit the round end of'the shank of the tool, and, as is usual, in this opening is fixed a sleeve 13' provided with a collar portion 13 to limit the inward movement of the tool. The outer end12 of the barrel 10 is formed to provide an inner shoulder 15, an externallythreaded cylindrical por barrel 10 by screwing an internally threaded portion 21 at the inner end of the sleeve on the externally threaded portion 16 of the The sleeve is screwed on to the barrel firmly so as to bring its innerend against the shoulder 17 of the barrel. The

sleeve is not detached from the barrel inv the i ordinary use of the device and may, there'- fore, be permanently secured to the handle bymeans other than the threaded connection which has been described.-

A rotatably mounted tool-engaging themher is located at the outer end of the sleeve and consists of a cap provided with an internally: threaded cylindrical flange 26 which is screwed on external threads 27 formed onthe outer portion of the sleeve '20. The cap 25 contains-a centralfopening 28 of a shape to fit onthe outerportion of the shank of the tool. In the drawimgs this portion of the tool shank and the openmg are square in form, but they maybe 'made of any other desired shape, except circular.

The retainer is provided with a non-rotary tool-engaging member to; hold the tool in the retainer in position tojbe-subjectedto blows of the hammer. In-the; tornrshown the non-rotaryengaging nieanscomprises a {plunger 30 slidably mounted Within the .sleevei20. and having disc+shapedzportion ,31 and cylindrical bearing;flange32. The

port-ion 31 iiswprovided with an;;elongated aperture To prevent rotation of. the plunger with. respects to .the; s'leeveythe plunger is providednvith keysB t-fixed in opposite-sides thereof and adapted to slide inner surface ofthe sleevo-2tl o. Y The plunger 30 is held between two compression spr ngs 40 and 41.. The spring 40 v longitudinally inikey-ways formed in the reacts between the gplunger and a locking member which is held against movement under thei thrust ot the spring; by engagerigid member. two

ment with the cap 25. The spring 40, therefore, tends to throwthe plunger 30 inwardly toward the hammer .'ll.---'The spring .41 reacts between the plunger ai' dthe'shoulder 15 of the barrel; This 5 spring therefore tends to throw. thelplungerawa-y from the hammer. The spring 40 is muehstronger "than the spring. ll-:50 that'the position in which the plunger isjnoi'nially heldIby-tho two springsinay be'varied by varying the position of the outer abutment :ofithe spring 40. Consequently the normal position of the v plunger maybe variedby adjusting theieap longitudinally with respect ,tc-Q the sleeve Thus, if the-cap 251s'screwedfurther 20. inward "on the threaded portion 27 of the sleeve 20, the plunger 30 is ,inoved inwardly towardythe' barrel 10, whilejitthe cap25 is screwed outwardly, 'the plunger isimoved further fromthe barrel. i

The locking member-5O serves t-o lock the cap 25against rota-tionwith respect mum sleeve- 20.; The-lockingmember consists o t an outer sleeve 51,,anfinner. ring 52, and

two :lKQYS; which extend radially between the sleeve and the ring and permanently secured to both otthe n so that the sleeve,

the ringg-and the keys form together a single Thewkeys pass through diametricallyt opposite longitudinal slots 54 whiclrare formed; in the outer portion of the sleeve 20and; extend to the outer portion 2 end of that sleeve. The sleeve 51 ot the locking member fits loosely againstthe outer surface of the cylindrical flange 26 of the cap 25. a The sleeve 51 has near itsinner end a shoulder Y which.fits-loosely against the outer surfaceFOfthe sleeve-20.; The ring 52 ot the locking member 1s carried by the keys in position to form an abutment for the outer end 0t the spring 40.

,li1e,-'cyl1ndrical flange 26 of the cap covcrs the outer portions of the slots in thefsleeve-QO,but does not extend far enough in to cover the inner ends of these vslots,even, when the cap screwedinwardly far as possible on the threaded 7 of the sleeve 20. In the inner edge oft-he cylindrical flange 26 are two open longitudinalslots or recesses 55 which are located at diametrically opposite points. The portions, 5 6 ot;-the-1nner, edge: of the flange are curved, having their lowest points 57 at from the recesses 55. WVhen theic'ap is turned so as to bring its recesses-55into L-alignment with the slots 5tiin1the sleeve 20 the keys 530i the'locking membcrienterthe reoessesoii, agshown inpFig. 2, and serve to prevent rotation of. the cap with respect to the sleeve; The keys are-retained intheslots 55 by the pressureot the spring 40 against ,t 10 ring 52 :ofthe lockingmember. lVhen the keys are inthemecesses; this pressure urges the-locking rfnemberoutwardly until .its outer edge ;1s brought into engagement with .an externalshoulder 58 formed on the ca'p 25 ;When -the;locking memb r is in this position, its sleeve :51 completely covers" and protects the threaded. portion :27 ,ot'. the

sleeveand -the-slots 54e- The keys may be withdrawn from thefrceessestfi so as to releasethe cap 25;.by, grasping theonter sleeve 51 and thawing; the;l.0ck1n ',n1e nber inwardly; against the force of. the spring 40 'unt1l:='thelock1n member'occupiesthe position shown in Fig. 1. if thecap 25 be then turned and the locking member be released,

inserted next. In inserting the pli'inger the keysfi are placedin the slotsfit at the outer. end of the sleeve 20 so that they slide into the keyways o' which extend from the inner ends, of the -.slots 54'. The locking member 50 is thenapplied to the sleeve 20,

the keys 53 placed, in. slots By grasping the outer sleevefil otthe locking member, the locking member inwardly against the force 40 so that .it uncovers the t-ion 27'at the outer end of the sleet-e20 ot the spring then pulled threaded por- The cap 25 is then appliedby screwing its internally threaded flange 26 upon the threads 27.

All the parts of the tool retainer may thus y be removed from the sleeve and a cod therein without detaching the sleeve 20 from the handle 10. In consequence any part of the tool retainer which has be come worn or injured may easily be replaced. I have found, however, that. after continuous use of the device in stone cutting for one year, the only parts of the tool retainer which require replaeeinei'it are the springs which may occasionally be broken.

, A tool 60, which is used with the retainer,

has a shank of the same general type as that of the tool described in my aforesaid Patent No. 1,ele'.3,461. The outer portion 61 of the tool shank is non-circular in cross-section, being shown as square. The inner portion 62 of the shank is cylindrical and smaller than the outer portion. On the cylindrical portion 62 are two dian'ietrieally opposite shoulders 63. The extreme width across these shoulders is greater than the width of the outer portion 61, and the square opening 28 in the cap is accordingly provided with two diametrically opposite recesses 64 to permit the passage of the shoulders 63 through the cap 25.

The operative portion -65 of the tool is detachably secured at theouter end of the shank in a manner "described in United States Patent No, Lei-58,171 issued to me on June 12, 1923. The screw 66 which secures the operative portion to the'shank is provided witha lock nut 67 in order that the screw may not be loosened by the vibration of the tool. While the cost of making the shank 61, 62 is necessarily somewhat greater than the cost of'an ordinary round tool shank. this fact does not add to the cost of operation of the pneumatic chisel, for since the operative portion 65 is detachably secured to the shank the shank may be used indefinitely by the substitution of a new operative portion for one which has become worn in use. I

lVhen the tool is tobe inserted in the tool retainer, the locking member is drawn in wardly to the position shown in Fig. 1, and the cap is turned through 90 from the position shown in Figs. 1 and 2, so that the keys blrest on the lowest points 57 of the curved portions 56 oil the inner edge of the flange 26 of the cap. This turning of the cap brings the recesses G l of the cap into alignment with the elongated aperture 83 inv the plunger 30. The shank of the tool is then inserted in the tool retainer, the shoulders 68 of the tool shank passing through the recesses 64 in the cap and through the aperture 33 in the plunger. The cap 25 is then turned through an angle of 90, bringingits recesses into alignment with the slots 54; inthe sleeve 20. As

soon as the position of alignment is reached the keys 53 of thelocking member 50 enter the recesses 55 and the locking member forced outward by the springrelO to the position shown in Fig. 2. The shoulders 63 of the tool shank then extend at right angles to the elongatedopening 38 in the plunger so that tne tool shankis held in the tool retainer and its longitudinal position therein is determined by the position. oi the plunger 30. v

Infusing he pneumatic chisel, the workn'ianpplaces onehand upon the barrel 10 and the other uponthe sleeve 20 or the sleeve 51 of the locking member. -He is thus enabled to guide the tool without grasping an oscillating part of the device. After the tool is driven lorward by each blow of the hammer, the spring 40 throws the tool inwardly into position to be sul jectcd to the next blow of, the hammer, and at the same time the spring 40 serves to press thelocking member 50 outward so that the keys 53 are held firmly in the recesses 55, eliminating all danger of a turning of the cap which would release the shoulders ofthe tool shank from the plun 'er 30.

In order to remove the tool from the retainer, the locking member is pulled inwardly to the position shown in Fig. 1, and the cap 25 is turned, usually by grasping the projecting portion 61 of the tool shank, until the keys 53 come against the lowest points 57 ofthecurved portions 56 of the inner edge of the flange 26 of the cap. This brings the shoulders 63, of the tool shank into hlignment with the elongated aperture 33 in the plunger 30 and releases the tool so that it may be withdrawn from the retainer. The proper position to which to turn the cap in order to release the tool is made ap- )arent by the release of the tool, which may be an by the hand whichis turning the tool and cap. After the tool has been withdrawn, the cap is held against accidental dis placement by the friction between the inner edge of the flange 26 of the cap and the keys 53 which are urged against the points 570i this edge by the spring ill. The cap is thus held in proper position for iheinsertion of another tool. v To regulate the force oil the hammer blows on the, tool it is necessary only to draw the locking member 50 inward to the position shown in Fig. 1, and then, while holding the locking member in this position, to screw the cap 25 further inwardly on the threaded portion 27 of the sleeve 20 if a stronger blow is required, or to screw the cap out wardly it a weaker blow is required. In either case, after the desired adjustment is made, the locking member 50 is released and the cap is turned until the keys 53 enter the I) in recesses 55, locking the cap andtool against furtnerturning. I

By actual use of thestoo'l retainer 'described, Ivhave ascertained that this adjust- Inent makes it possible tofposition the tool I either so that it receives the full force of the hammer blows, or so' that it IS normally, Just out of reach of the hammer where it is not struck by the hammer except when the operative portion of the tool is pressed against the work] A pneumatic, chisel provided with'the tool retaineris', therefore, adapted both for the heaviest rough cutting, and for- 'fine carving, aswell' as for any intermediate grade of work The workmanls control-of the force of the hammer-blowsis fully as complete "as that which 1satta1nedwhen the workman actually grasps the shank of the" toolwithihishand, while at the same time the, 'workinans hand isielieved of substantially all vibration y a) lVhat I claim is: 1

The combination with a barrel containing reciprocatory hammer and a tool to be driven by said hammer, of a toolbretai-ner secured to the barrel and having a relatively strong spring tending to urge the toolatoward the hammer, and .a relatively weak spring tending to urge "the tool away from the hammer.

The combination with a barrel containing a reclprocatory hammer and a tool to be driventby sal'dlhainmer, of a: tool retainersecured to the barrel and havinga spring tending. to urge the tool toward thehannner, springtending to urgethejtool away :trom

the hammer, and means for v .ying the nor.-

vinal position in which theftool is held by said springs between a vposition 1n which the tool receives the full force of the blows of the ha nen and a position in which the too]. out of reach of the hammer.

The combination'with a barrel containing' a reciprocatory hammer-and a tool to be driven by said hammer, 0t a tool retainer secured tothe barrel and having a slidably mounted, member engaging the' tool, a relativelyweak spring engaging the inner side oi said slidable member, an abutment for the inner. end ofsaid'spring in fixed relation torthe barrel, a relatively strongspring engaging the outer side oi said slidable meman abutment for theouter end or said ing, and means for adjusting said abutment toward and away from the barrel to vary the normal position of the tool with resnect to the hammer. a

l The combination witth a barrel contaizr i'reciprocatory hammer and a tool havin a shank, the outer portion of which is non-circularin cross-section and the inner portion of which is of lessdiameter than'tne outer-portion and PlOVldECl with a shoulder, of a tool retainer secured to said barrel'and provided with a first" disc containing an "elongated aperture to permit the passage of said shoulder when the tool is turnedwin one direction relatively thereto, a second disc containing an aperture fittingthe' non-cirthrough said cap and engaging said plunger, l

a relatively weak spring reacting between said barrel. and said plunger-,a relatively strong spring reacting between said plunger and said cap, and means for adjusting said cap longitudinally of the sleeve to vary the normalposition of the plunger andtool with respect to thel ammera r 6. The combinationwith a berrel containing a reciprocatory hammer and'a tool having a shank, the outer portion of lwhich'is' non-circular in cross-section and the I inner portion of which is provided with ashoulder, of a tool retainer comprising a sleeve sur-, rounding the shank of the tool and attached j the l a'rrel, a plunger in said sleeve having an aperture through whic'lrthe shoulder on the tool shank may vpass when the tool is turned in one direction, means for preventing rotationof theplunger with respect to i the sleeve, a cap mounted on the sleeve for longitudinal and rotary movement with respect thereto and containing an aperture fitting the non-circular portion of the tool shank, a relatively weak spring reactlng between thebarrel' and the plunger, a' rela tively strong spring reacting between the plunger and the cap, means for adjusting the cap longitudinally of the sleeve,and releasable locking means adapted to lock the cap to the sleeve in any longitudinal position ofthe cap when the cap is turned so that the shoulder on the tool shank isout of alignment with the aperture in the plunger.

I. The combination with a barrel contain ing a reciprocatory' hammer and a tool having a shank, the outer portion of which is non-circular in cross-section and the inner portion of which'is provided wi-th a shoulder,

of a t'ool retainer comprising a sleeve attached to the barrel and having a threaded outer portion. a qlunger in s ald sleeve having an aperture trough wh ch the shoulder on tl're toolshank may pass when the tool is turned in one directiomnieans for preventnig rotation 01"- the plunger 1 with respect to the's'le'eve, a cap having athreaded portion llw adapted to pei'mitthe passage 'of thshoul- 1easab1e-10cking means for restrainingrotm ders ofithe tool'shank when the tool is turned tion of the second disc with respect to the in'one direction, asec'ond disc containing an first disc; 5 i ap rt 'ng he non ircular port-ionof Iniestimdny whereoflliave hereunto set the 'tool shank and tworecessesextending myhan'd; T

fromsaid aperture to perm-it the passage of i: v f the shoulders through the aperture, and re- 1 LIOHN SHEARMAN DONALDSON. 

